Improvement in steam safety-valves



UNITED STATES PATENT OEEICE.

JOHN N. WRIGLEY AND GEORGE SMITH,A OF NEWARK, NEW JERSEY, ASSIGNORS TO JOHN N. VRIGLEY, OF SAME PLACE.

IMPROVEMENT IN STEAM SAFETY-VALVES.

Speciiication forming part of Letters Patent No. 69,527, dated October 1, 1867.

To all whom it may concern Be it known that we, JOHN N. WRIGLEY and GEORGE SMITH, of Newark, in the county of Essex and State of New Jersey, have invented a new and useful Improvement in Safety-Valves; andwe do hereby declare that the following is a full, clear, and exact description thereof, which will enable others sk illed in the art to make and use the same, reference being had to the accompanying drawings, forming part of this specification.

This invention consists in the arrangement of a valve and valve-scat in the shell, thereby rendering it much more sensitive than the ordinary safety-valve now in use, and consequently much more safe.

Figure 1 is a vertical section of the safetyvalve complete, it being through the line .c .1: ot' Fig. 2, showing the position of the valve in the chamber and the form of the shell and seat. Fig. 2 is a cross-section of Fig.1 through the line y y.

Similar letters of reference indicate like parts.

A represents the casting or shell, which is attachedV to the boiler in the ordinary manner. In this example of our invention the valve is fixed or stationary, and it is the seatwhich rises, the seat being cylindrical in form, surrounded by an internal chamber; but this ar-f rangement may be reversed and the seat made stationary and the same e'ect be produced.

B represents the stationary valve, and C represents the cylindrical seat covering the valve. An annular space on the seat around the valve presents an area upon which the steam from the boiler acts.

D is the internal chamber, which is formed around the valvesseat C.

E is the stem, which is attached to or forms a part of the valve-seat.

F is the safety-valve lever.

The steam from the boiler enters at G, and after passing through into the chamber D, escapes atH. As soon as the pressure of the steam in the boiler raises the seat C it escapes into the chamber through orices a, and also at the bottom of the seat at c, when there is an equilibrium of pressure at once produced, so that the movement ot1 the seat is controlled by avery light weight on the safety-valve lever F. Being thus balanced, or as nearly so as may be desired, by the steam in the chamber D, the seat is extremely sensitive to pressure and becomes (what the ordinary arrangement is not) a real safety-valve.

What we claim as new, and desire to secure by Letters Patent, is-

1. The construction and arrangement in the shell A, of the stationary valve B, and movable valve-seat C, substantially as herein set forth, for the purpose specified.

2. The construction and arrangement of the shell A, stationary valve B, movable valveseat C, stem E, and lever F, substantially as described, for the purpose specified.

JOHN N. WRIGLEY. GEORGE SMITH.

Witnesses:

WM. F. MCNAMAEA, ALEX. F. ROBERTS. 

